1. Field of the Invention
The present invention is in the field of removing photoresist and other materials from microcircuit substrates in the manufacture of integrated circuits.
2. Description of Background Art
An integral part of microelectronic fabrication is the use of photoresists to transfer an image from a mask or reticle to the desired circuit layer. After the desired image transfer has been achieved, the photoresist is removed by stripping before proceeding to some subsequent process step.
Contamination by mobile ions, especially by sodium ions, is responsible for many failures of integrated circuits, especially during high temperature operation bias burn-in tests. Mobile ion contamination may be introduced at various stages during integrated circuit fabrication.
Those concerned with the development of integrated circuit technology have continuously sought for materials and techniques to reduce mobile ion contamination. In U.S. Pat. No. 5,417,802, crown ethers were used to sequester Group I and Group II ions in organic solvents used for photoresist removal.